POS1157 WARFARIN VS DOACS IN A REAL-WORLD DATA
Authors: O. Carmi, T. Madjar, T. Hornik-Lurie
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Antiphospholipid syndrome (APS) is a syndrome which consists of vascular thrombotic events, arterial or venous, with the presence of persistent circulating antibodies. APS patients have a highly variable risk profile, derived from their different medical risk factors and diverse antiphospholipid antibodies (aPL) profile. The current mainstay for the treatment of APS is anticoagulation with Vitamin K antagonists (VKAs). The primacy of Warfarin has been challenged by the introduction of direct oral anticoagulants (DOACs), stems from DOACs convenience, constant dosing, without the need for blood test monitoring and almost no drug interactions. However, the TRAPS study that compared Rivaroxaban to Warfarin treatment in APS patients was terminated prematurely due to higher incidence of thrombotic events in the Rivaroxaban group [1]. Yet, all patients on the TRAPS trial were triple-aPL positive. Similar conclusions were demonstrated on the ASTRO study that compared Apixaban to Warfarin treatment [2]. Because the risk profile of APS patients is heterogeneous, both clinically and serologically, it is difficult to conclude that treatment with DOACs is generally inferior to VKAs for all APS patients, for instance in the low-risk patient population. <h3>Objectives</h3> We assume that under real-life circumstances, VKAs narrow therapeutic range and the constant need for repeated INR checkups may change the above studies outcomes. Hereby, the aim of this study is to compare real-life outcomes of APS patients treated with DOACs to patients treated with Warfarin from the aspect of thrombotic events reoccurrence on one hand and bleeding events on the other hand. We also checked the outcomes specifically for different APS risk profile subgroups under different treatments with either Warfarin or DOACs. <h3>Methods</h3> 139 non obstetric APS patients from "Meir" medical center were followed up retrospectively for a mean period of 16 years, since diagnosis time until 31/12/2022. We gathered data on patients SLE status, aPL profile and type of thrombotic event at the time of diagnosis. We checked for thrombotic events reoccurrence and bleeding events (including their types) with respect to the specific treatment at the time of each event. <h3>Results</h3> Of 139 followed-up patients, we report a total of 217 thrombotic and 60 bleeding events. From the Warfarin treated group, 178 (82%) thrombotic events were recorded, 130 (74%) of them occurred in the high risk serological profile patients. From the DOACs treated group, 39 (18%) thrombotic event were recorded, 23 (59%) of them occurred in the high risk serological profile patients. 59 (98%) bleeding events were recorded in the Warfarin treated group, 46 (82%) among the high risk profile group. only one bleeding event was recorded in the DOACs group. <h3>Conclusion</h3> According to our single center data gathered retrospectively form a follow up of real- life APS patient's treatment, Warfarin vs DOACs, we found higher incidence of thrombotic events (82%) in the Warfarin group compared to the DOACs group (59%). High risk profile patients had a higher thrombotic incidence in both groups. Moreover, patients taking Warfarin had a dramatically higher incidence of bleeding events comparing to DOACs (98% vs 0.01% respectively). These findings may raise the differences between real-life and controlled researches and may challenge the superiority of Warfarin. More researches are needed in order to answer this question. <h3>References</h3> [1]Pengo, V, Hoxha, A, Andreoli, L, et al. Trial of Rivaroxaban in Antiphospholipid Syndrome (TRAPS): Two-year outcomes after the study closure. <i>J Thromb Haemost</i>. 2021; 19: 531– 535. https://doi.org/10.1111/jth.15158 [2]Woller SC, Stevens SM, Kaplan DA, et al. Apixaban for the secondary prevention of thrombosis among patients with antiphospholipid syndrome: study rationale and design (ASTRO-APS). Clin Appl Thromb Hemost 2016; 22: 239–247. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.